Adjustable piston



Fig. 1.

l I l Patented Feb. 12, 1933 UNITED STATES ADJUSTABLE PISTON Kenneth A. Clark, Waterloo, Iowa, assignor of one-third to Harold 0. Roepe and one-third to Nels O. Madsen, both Application December 4, 1933, Serial No. 700,772

3 Claims.

My invention relates to improvements in pis tons for internal combustion engines, and the object of my improvements is tofurnish a sectional piston of a simple and inexpensive construction, and which has its elements so relative- .ly arranged as to be capable of their radial as also their longitudinal adjustment.

In this class of pistons a piston must have small clearance in a cylinder in order to maintain compression without leakage of gas while in combustion or oil passage by the piston other than for suitable lubrication, or intrusion into the combustion chamber of crank-case oil. Pistonslap must be avoided, and my invention prevents this as the skirt element of the piston is constructed and adjustable for this purpose. The skirt is thus adapted to the cylinder wall for proper coaction notwithstanding wear of either or both.

A single means of adjustment for the above purpose also is effective in extending the piston length as may be necessary at times for different engines. My invention further saves weight of many or complicated parts such as are known in some other pistons.

I have in my invention accomplished all of the above objects in actual reduction to practice and by the means which are hereinafter described and claimed, and which are illustrated in the accompanying drawing, in which Figs. 1 and 2 are central longitudinal sections of my improved assembled piston taken 'at approximately a right angle-apart. Fig. 3 is a central longitudinal section of the skirt element alone. Fig. 4 is a top plan of said skirt element alone, and Fig. 5 is a top plan of one of the shims.

The body or head part of my piston 1 may have a number of ring grooves 2 toreceive the usual piston rings not shown, and its body has a dimin- 40 ished portion 1' whose medial zone is cylindrical, and which has at top and bottom frusto conical outer annular faces 13 and 14 respectively. The body 1 has the usual alined pairof wristpin bosses 6 with bearing seats 6' for a wrist-pin not shown. A lubricationpassage 11 is provided in each boss.

The skirt element 12 is longitudinally hollow and its inner wall beginning at the top as illustrated has interiorly a coned part 15 to fit slidably about the coned face 13 of the body 1, having below a cylindrical inner face to fit likewise upon the medial outer face of the body part 1', and having below the latter face a fitting coned face 16 to fit also slidably upon the said coned face 14, an annular cylindrical inner face 17 being just beof Waterloo, Iowa low the coned face 16. I The lower end of the skirt has a narrow inner fiange interrupted oppositely by inwardly extending radial bosses 8 having tops in the same diametrical plane and provided with interiorly threaded holes 8' alined longitudinally with interiorly threaded sockets 7 in downward extensions 5' of said wrist-pin bosses 5, the lower ends of said extensions being spaced apart at from the said flanged bosses 8. Headed screws 9 are seated in the unthreaded seats 7 and 8' for securing the skirt 12 in' longitudinally adjusted positions upon the body part 1'. The skirt 12 has at one side therethrough the inclined split 18, and the piston parts 1 and 12 are of resilient metal, or the skirt has a suitable degree of resiliency, to permit of its expansion or contraction radially as operated upon by the screws 9, as the inclined zones and 16 slide upon the outer fitting like coned zones 13 and 14 of the body, causing by pressure or release of pressure the desired amount of such expansion or contraction of the skirt to cause it to fit closely the inner bore of an inclosing cylinder wall adjustably.

It will be seen that when initially fitting the piston to the cylinder, and the amount of necessary adjustment has been thus ascertained, one or more shims 19 may be seated on the stems of the screws 9 to fill the interspaces of the bosses 8 and the lower ends of the extensions 5', as the shims have holes 20 for that purpose. These shims filling the cavities 10 between the bosses 8 and the extensions 5 secure the skirt in its adjusted position tightly without possibility of looseness of the skirt upon the body 1. The cylindrical fit'at 1' between the body and skirt is such as to prevent any sideplay of the skirt in any adjusted position of the coned fittings.

I claim:

1. A headed hollow piston comprising a head part and a singly longitudinally split resilient skirt part having longitudinally spaced conical faces slidably associated with complementary faces on the head part, the conical faces on each part being connected by a cylindrical face, means for securing said parts in a desired longitudinal adjustmentupon each other to efiect also a desired radial expansion or contraction of the skirt part.

2. A headed hollow piston comprising metal sections consisting of a hollow head part and a longitudinally singly obliquely split resilient skirt part mounted thereon, said parts having cylindrical medial zones and having complementary coned fitting zones at the ends of the medial zones, and said parts having spaced apertured portions,

adjustable fastening means mounted in said portions and actuable to slidably move the skirt longitudinally upon the head part, to efiect expansion or contraction of the skirt part radially while the latter is moving to or fro upon the head part longitudinally.

3. A headed hollow piston comprising metal sections consisting of a hollow head part and a longitudinally obliquely singly split resilient skirt part mounted thereon, said parts having cylindrical medial zones and having complementary coned KENNETH A. CLARK. 

